As for the production of a dimethylpolysiloxane with a low polymerization degree (which is sometimes called "a dimethylpolysiloxane oligomer", hereinafter); there have so far been known the equilibration reaction between hexamethyldisiloxane and octamethylcyclotetrasiloxane in the presence of sulfuric acid as a catalyst (U.S. Pat. No. 2,469,888) and the method of using the simultaneous hydrolysis reaction of trimethylchlorosilane and dimethyldichlorosilane (U.S. Pat. No. 2,398,672).
However, those methods cannot produce an intended dimethylpolysiloxane oligomer alone in view of the characters of the reactions adopted therein, and so both yield and pot yield shown thereby are low. Further, it takes a long time to isolate the intended dimethylpolysiloxane oligomer alone from the reaction mixture by fractional distillation. Accordingly, they are at a disadvantage in entailing a high production cost.
Recently, the range of use of dimethylpolysiloxane oligomers has been increasing in various industrial fields, e.g., as cleaning agents for machine parts. In proportion thereto, requirements for reduction in the production cost of such oligomers and the steady supply thereof have been growing.